Case studies have been used in undergraduate science education as a way to develop students' critical thinking and problem-solving skills. However, little empirical evidence exists on whether this teaching method is having the desired impact on students in plant pathology courses. This study evaluated the influence of the case teaching method on students' problem-solving and critical thinking skills in an undergraduate plant pathology course. Specifically, the course utilized both traditional lecture-based teaching as well as case study methodology. Students completed a problem-solving test that gave them four problem scenarios similar to two that were taught by lecture and two that were taught by case studies and examined students' ability to critically think and problem solve. We also investigated students' attitudes and feelings toward the case study approach assessed via a 22-item Likert-scale survey. A paired sample t-test comparing the lecture vs. case study method suggested that the case study approach was more beneficial in helping students develop applied problem-solving skills. The survey results demonstrated that students had more positive attitudes toward the case study teaching approach. For the applied plant science students, the diagnosis of plant health problems is one of the most difficult skills to develop. The results from this study indicate that case studies helped students develop critical thinking skills required to diagnose plant health problems while actively engaging them in the course content. (Contains 3 figures.)